Re: [Qemu-devel] [PATCH COLO-Frame v10 14/38] COLO: Load VMState into qsb before restore it

[zhanghailiang]

On 2015/11/14 0:02, Dr. David Alan Gilbert wrote:
> * zhanghailiang (address@hidden) wrote:
> > We should not destroy the state of SVM (Secondary VM) until we receive the whole
> > state from the PVM (Primary VM), in case the primary fails in the middle of 
> > sending
> > the state, so, here we cache the device state in Secondary before restore it.
> >
> > Besides, we should call qemu_system_reset() before load VM state,
> > which can ensure the data is intact.
> >
> > Signed-off-by: zhanghailiang <address@hidden>
> > Signed-off-by: Li Zhijian <address@hidden>
> > Signed-off-by: Gonglei <address@hidden>
> > Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> > ---
> >   migration/colo.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
> >   1 file changed, 46 insertions(+), 1 deletion(-)
> >
> > diff --git a/migration/colo.c b/migration/colo.c
> > index 25f85b2..1339774 100644
> > --- a/migration/colo.c
> > +++ b/migration/colo.c
> > @@ -287,6 +287,9 @@ static int colo_wait_handle_cmd(QEMUFile *f, int 
> > *checkpoint_request)
> >   void *colo_process_incoming_thread(void *opaque)
> >   {
> >       MigrationIncomingState *mis = opaque;
> > +    QEMUFile *fb = NULL;
> > +    QEMUSizedBuffer *buffer = NULL; /* Cache incoming device state */
> > +    int  total_size;
> >       int fd, ret = 0;
> >
> >       migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
> > @@ -310,6 +313,12 @@ void *colo_process_incoming_thread(void *opaque)
> >           goto out;
> >       }
> >
> > +    buffer = qsb_create(NULL, COLO_BUFFER_BASE_SIZE);
> > +    if (buffer == NULL) {
> > +        error_report("Failed to allocate colo buffer!");
> > +        goto out;
> > +    }
> > +
> >       ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY, 0);
> >       if (ret < 0) {
> >           goto out;
> > @@ -337,19 +346,50 @@ void *colo_process_incoming_thread(void *opaque)
> >               goto out;
> >           }
> >
> > -        /* TODO Load VM state */
> > +        /* read the VM state total size first */
> > +        total_size = colo_ctl_get(mis->from_src_file,
> > +                                  COLO_COMMAND_VMSTATE_SIZE);
> > +        if (total_size <= 0) {
>
> Error message?

OK, we need one.

> > +            goto out;
> > +        }
>
> OK, and when you fix up the colo_ctl_get in the previous patch to
> take a separate pointer for value, you can make total_size a size_t.

Yes, i have updated it after addressing your review comment on patch 11.

> Other than those, it looks good.

Thanks.

> Dave
>
> > +        /* read vm device state into colo buffer */
> > +        ret = qsb_fill_buffer(buffer, mis->from_src_file, total_size);
> > +        if (ret != total_size) {
> > +            error_report("can't get all migration data");
> > +            goto out;
> > +        }
> >
> >           ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED, 
> > 0);
> >           if (ret < 0) {
> >               goto out;
> >           }
> >
> > +        /* open colo buffer for read */
> > +        fb = qemu_bufopen("r", buffer);
> > +        if (!fb) {
> > +            error_report("can't open colo buffer for read");
> > +            goto out;
> > +        }
> > +
> > +        qemu_mutex_lock_iothread();
> > +        qemu_system_reset(VMRESET_SILENT);
> > +        if (qemu_loadvm_state(fb) < 0) {
> > +            error_report("COLO: loadvm failed");
> > +            qemu_mutex_unlock_iothread();
> > +            goto out;
> > +        }
> > +        qemu_mutex_unlock_iothread();
> > +
> >           /* TODO: flush vm state */
> >
> >           ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED, 0);
> >           if (ret < 0) {
> >               goto out;
> >           }
> > +
> > +        qemu_fclose(fb);
> > +        fb = NULL;
> >       }
> >
> >   out:
> > @@ -358,6 +398,11 @@ out:
> >                        strerror(-ret));
> >       }
> >
> > +    if (fb) {
> > +        qemu_fclose(fb);
> > +    }
> > +    qsb_free(buffer);
> > +
> >       qemu_mutex_lock_iothread();
> >       colo_release_ram_cache();
> >       qemu_mutex_unlock_iothread();
> > --
> > 1.8.3.1
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK
>
> .